Thanks to a combination of an intense El Niño weather pattern, marked by a burst of warming in the Pacific, and long-term human-caused climate change, 2015 is poised to be the hottest year on record by a significant margin.

The Pacific Ocean wasn’t the only region experiencing uncharacteristically high temperatures in November, however. As ClimateProgress’ Joe Romm recently wrote, “It was so warm that… parts of the Arctic and Siberian permafrost were a staggering 10.2 degrees C (18 degrees F!) warmer than normal. That is particularly troubling since the permafrost contains twice as much carbon as the atmosphere, and as it defrosts, it releases that carbon in the form of either CO2 or methane (CH4), which is 84 more times more potent at trapping heat than CO2 over a 20-year period.”

While one of the strongest El Niños on record is driving up temperatures this winter, a recent analysis by Climate Central found that carbon pollution emitted by human activity is by far the biggest driver of warming, while natural factors like El Niño account for a much smaller percentage.

Thirteen of the 14 hottest years on record took place in the 21st century ...